Fabrication and magnetic properties of nanopatterned FePt media

Abstract

A method for fabricating nanopatterned media has been investigated. A monolayer of regularly distributed Ni nanoparticles of uniform diameter (similar to 5 nm) fabricated on the surface of a polyimide-coated Si substrate using metal film-polyamic acid interactions was utilized as a protruding template to deposit an array of FePt phase. A FePt film (5 nm thick) was sputtered onto this template with or without an underlayer of either 5-nm-thick MgO or CoO and analyzed before and after annealing. It was observed that while the FePt films sputtered on flat Si substrates with underlayers exhibited low H-c of only about 1 kOe after the L1(0) conversion, the FePt samples deposited onto protruding Ni nanoparticle templates showed a significant increase in H-c to similar to 8.1 kOe. The FePt sample with CoO underlayer exhibited a possibly strong perpendicular magnetic anisotropy. The intergranular exchange coupling of the samples was also investigated by using Delta M method.